Distillation



Filed Dec CHARGE STOCK 33 I LIGHT ENDS AND STE AM STR\PPER CHAMBER STEAM PQ M. WADDILL DISTILLATION 4 Sheets-Sheet 1 FIG.

43 42 4 g v 49 v I n I 46 I8 2 LIGHT GAS 38 42 23 37 .1 Mai -4 27 i P HEAVY glr'ia' :=J 39 I As OIL P RESIDUUM v 34 INVENTOR. P.M.WADDILLI A T TORNE YS July 28, 1959 P. M. WADDlLL DISTILLA'IION Filed Dec. 13, 1954 4 Sheets-Sheet 2 FIG. 3A

INVEN TOR. P. M .WADDILL 7 July 28, 1959 P. M. WADDILL DISTILLATION I 4 Sheets-Sheet 3 Filed Dec; 13. 1954 FIG. 4

\/ QQQ Q Q v 7 To VACUUM MEANS FIG. 6

RESIDU um INVENTOR. P.M. WADDILL A T TORNE YS July 28, 1959 P. M. WADDILL 7,

DISTILLATION Filed Dec. 15. 1954 4 Sheets-Sheet 4 A T TORNE Y5 DISTILLATION Paul M. Waddill, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Application December 13, 1954, Serial No. 474,664 33 Claims. (Cl. 208-364) This invention relates to apparatus and method for the distillation of liquids. In one aspect this invention relates to the reduction of entrainment in vapors from flashing a heavy liquid, by first stripping lightcomponents from the liquid, prior to flashing same. In one aspect this invention relates to a distillation method comprising subjecting a distillable material to flashing and then to condensation of resulting vapor so as to form clean distillate product fractions and residues of improved high average molecular weight. In one aspect this invention relates to apparatus comprising in combination a first upright chamber for stripping light ends from a heavy liquid feed to be distilled, and second upright chamber adapted to receive stripped feed from the said first chamber for distilling said feed and for condensing fractions of vapor thus formed. In another aspect this invention relates to a vacuum distillation method comprising subjecting a heavy hydrocarbon oil to flashing and condensation of resulting vapors in an upright distillation chamber to form clean gas oil condensate product and high softening point residual pitch. In still another aspect this invention relates to apparatus comprising an upright distillation chamber containing cooling-spray and condensing-spray means, and condensate product collection means, adapted and arranged to provide for distillation of heavy liquids, and when applied to vacuum distillation providing for improved high vacuum and at low pressure drop across the distillation zone.

In the vacuum distillation of heavy liquids, wherein feed is first flashed and then resulting vapors are condensed to form product fractions, distillate fractions are obtained which are contaminated with unvaporized portions of liquid feed as a result of entrainment of the latter in vapors formed, and condensation of the entrainment-containing vapors. Thus, in the vacuum flash distillation of hydrocarbon residua, distillate fractions having high carbon residues have been obtained together with residual pitch or tar fractions in high yield. As a result of the entrainment in vapors formed during the flashing of feed, condensate products are formed which are contaminated so that their utilization for a predetermined use is impaired. For example, high carbon residue gas oils are undesirable as feed stocks for various hydrocarbon conversion processes.

My invention provides for apparatus and method whereby a heavy liquid is distilled without the presence of entrained feed particles in vapors formed from flash vaporization, so that condensate product fractions are provided, free from unvaporized feed particles as contaminants, which fractions exhibit especial utility as feed stocks for various conversion processes.

nited States Patent My invention also provides apparatus and process for eflecting distillation of a heavy liquid, which when employed under subatmospheric pressures provide for im-' proved conditions of high vacuum and low pressure drop said chamber; a first liquid collecting means above the communication of said inlet conduit means with said chamber, disposed in said chamber and adapted to permit vapor flow upwardly in said chamber from a point below to a point above said first liquid collecting means and above said first liquid collecting means into unobstructed contact with a spray from a first spray means described hereinafter; a first spray means in said chamber spaced above said first liquid collecting means and so adapted and arranged as to direct spray into said vapor flow to condense at least a portion of said vapors and to cause condensate thus formed to collect in said first collecting means; a second liquid collecting means disposed in said chamber above said first spray means and adapted to permit vapor flow upwardly in said chamber from a point below to a point above said second liquid collecting means and above said second liquid collecting means into contact with a spray from a second spray means described hereinafter; a second spray means in said chamber above said second liquid collecting means so adapted and arranged as to direct spray into contact with vapors above said second liquid collecting means to condense at least a portion of said vapors; a collecting tray disposed below said second spray means and above said second liquid collecting means and transversely of vapor flow above said second liquid collecting means; means for conveying liquid from said tray to a point substantially vertically above said second liquid collecting means; conduit means corn municating with an upper portion of said chamber above said second spray means and with a point outside said chamber; conduit means communicating with a point in said chamber below the point of communication of said inlet conduit means, with a point outside said chamber; conduit means communicating with said first liquid collecting means and with a point outside said chamber; and conduit means communicating with said second liquid collecting means and with 'a point outside said liquids comprising an upright chamber such as described,

hereinabove, having its inlet conduit means (for introducing feed) connected with a second upright chamber Patented July 28, 1959 in which liquid to be flashed is stripped to free it from relatively light components, which otherwise will cause entrainment in vapors formed in the flash distillation step. In the said second chamber, i.e., for stripping of feed, there is provided baffle means in a lowermost portion adapted to cause fluid passing therethrough to follow a tortuous path, together with inlet conduit means for introducing a stripping gas such. as steam in contact with feed to be distilled, passing countercurrently along the said tortuous path as a film or a layer. In a preferred form the said stripping chamber portion, containing the baffle, is of smaller cross section than the remainder of said chamber.

In accordance with still another concept of this invention is provided a method for distillation of liquids which comprises introducing such a liquid into a lower portion of. an upright distillation zone; passing. vapors from said liquid in the said zone upwardly to a point above a first liquid collecting means and above said means into unobstructed contact with a cooling spray so as to condense at. least a portion of the said vapors into the first liquid collecting means; passing remaining uncondensed vapors upwardly to a point above a second liquid collecting means and above the said second liquid collecting means into contact with a condensing spray to condense remaining vapors; collecting condensate in a condensate collector means disposed beneath said condensing spray and so adapted and arranged as to transfer said collected condensate to said second liquid collecting means while preventing contact of upwardly rising vapors with said condensate being transferred; transferring collected con densate from said condensate collector means to the said second liquid collecting means, and recovering condensate from each of the said first and second collecting means.

My invention is illustrated with reference to the drawings.

Figure l is illustrative of a preferred form of distillation apparatus employed alone or in combination with a feed preparation chamber wherein light components are stripped from the feed prior to distillation of same, Figure 1 also provides a diagrammatic illustration of my process.

Figures 2A, 2B and 2C, respectively, show perspective, cross sectional plan and side views of preferred arrangements of battle and spray assemblies of Figure 1. Figure 2D shows a plan view of a preferred arrangement of baflles employed in the above said baflle assembly.

Figure 3A shows a front view of a liquid collector means and vapor condensation means of Figure 1. Figure 3B shows a preferred arrangement of spray nozzles employed to effect initial condensation of vapors from flashing.

Figure 4 shows a preferred arrangement of spray nozzles employed as condensing and/or cooling sprays of Figures 2 and 3; i.e., the nozzles are preferably disposed in a plurality of rows on about I- to 2-foot centers on equilateral triangles. It is important that the spray cover the entire area through which the vapors flow.

Figure 5 is illustrative of a form, other than that of Figure 1, of distillation apparatus and method of my invention, wherein liquid collecting means are disposed in a central portion of the distillation chamber rather than adjacent the side wall thereof and wherein sprayed droplets are emitted in a direction opposite that of sprays of Figure 1.

Figure 6 is illustrative of an arrangement of fins or other flow directing means, which in one embodiment facilitates recovery of condensate product described hereinafter.

Figure 7 shows a liquid collector means similar to c01- lector 12 of Figure 1 with which is associated a spray nozzle assembly adapted to emit spray toward the chamber periphery from a locus of points extending upwardly from the collector means to a central' chamber A portion. Figure 7 also shows, associated with the said spray assembly, a plurality of deflector baflles extending laterally from the said locus for facilitating liquid vapor contact.

Figure 8 shows a liquid collector means similar to collector 12' of Figure 5 with which is associated a spray nozzle assembly adapted to emit spray from a locus extending upwardly from the collector toward the chamber periphery toward a central chamber portion. Also shown associated with the said spray assembly is a plurality of baflles extending from the said locus toward a central chamber portion for facilitating vapor-liquid contact.

Figures 9a and 9b show such deflector baflie members of Figures 7 and 8.

The structure of Figures 7 and 8 can be employed when desired in lieu of structures in Figure 1 embodying elements 12, 13, 14 and 13a, and in Figlre 5 embodying elements 12, 13 and 13b.

This invention is applicable to the distillation, under any suitable distillation conditions of temperature and pressure, of any distillable material such as for example vegetable, animal or mineral oil, distillable organic and inorganic chemical mixtures or solutions, and juices, such as in low-temperature flash distillation of water from fruit and vegetable juices, for example in the concen tration of orange or other citrus juices by flashing water therefrom. In a preferred form this invention is applied to vacuum distillation of oil stocks, such as reduced crude, fuel oil, cracking still residue, cylinder stock, cracked topped crude, or the like, as for example a residuum from topped crude cracking having a gravity of from about -5 to 5 API and a viscosity of 210 F. generally above 20 S.F.S., a heavy hydrocarbon oil such: as that produced by vis-breaking, and the like. ..c cordingly, for purpose of illustration, the present inven tion is discussed, with reference to the drawings, in terms of vacuum distillation of heavy hydrocarbon oils.

With reference to Figure l, inlet conduit means 19 connects with a lower portion of upright chamber ll, containing a first liquid collecting means 12 above the point of communication of conduit 10 with the interior of chamber 11 and is disposed in chamber ll so as to permit vapor flow upwardly through collecting means 12 into unobstructed contact with liquid spray emitted" from spray assembly 13 adapted and arranged so asto direct spray into vapors passed through collecting means 12 so as to condense at least a portion of the said vapors and to cause resulting condensate to collect in the collecting means 12. Collecting means 12 is pref-- erably a trough above the said inlet conduit adjacent the inner wall of the chamber and transversely disposed therein, and spray assembly 13 is preferably adapted soas to form the sides of an upright member therein. Plate, or ba'lfle means, 14 closes the upper end of the. upright member formed by sprays 13 thereby deflecting. flow of vapors in contact with spray from assembly 13.. Liquid collecting means 16 is disposed in chamber 11 above spray assembly 13 and adapted to permit vapor flow upwardly therethrough into contact with spray from spray assembly 17 described hereinafter. Horizontally disposed spray means 13a located below collecting means 16 and above plate means 14 is adapted and arranged so as to direct liquid spray downwardly. Collecting means 16 is advantageously a trough transversely dis posed in chamber 11. Condensate collector tray 13 is disposed below spray means 17 and above collecting means 16 and transversely of vapor flow above collecting means 16. A baffle assembly 19 is disposed above liquid collecting means 16 in close proximity to spray assembly 17 so as, with spray assembly 17, to form side Walls of an upright enclosure. Tray 18 preferably forms the bottom end of the last said enclosure and extends laterally beyond spray assembly 17 so as to collect liquid as described hereinafter.

Spray is directed from assembly 13 preferably toward the periphery of chamber 11. Liquid from spray assembly 17 is directed preferably toward baflie 19.

Conduits 21, in communication with the upper side of tray 18, are adapted to convey liquid from tray 18 to a point substantially vertically above liquid collecting means 16, conduits 21 thereby conveying liquid from the said tray into collecting means 16. Alternatively, conduits 21 can comprise liquid flo'w deflecting means for directing overflow from tray 18 into collecting means 16. Conduit 22 conveys liquid from collecting means 16 to a point outside chamber 11 and conduit 23 conveys liquid from collecting means 12 to a point outside chamber 11. Conduit 24 is connected with a lower portion of chamber 11 for withdrawal therefrom of liquid.

In a preferred form, a lowermost portion 26 of chamber 11, disposed below the point of communication of inlet conduit therein is of cross section smaller than that of the remainder of chamber 11, whereby to facilitate the collection and withdrawal of unvaporized feed portions of residual product. Spray assembly 27 is, in a preferred form, disposed in chamber 11 and connected with conduit 10 so as to direct feed from conduit 10 as a spray toward the bottom end of chamber 11.

Closure means 14 in chamber 11 is preferably a dome plate and is preferably insulated on its upper surface for reasons discussed thereinafter, whereby undue cooling of the dome plate together with concomitant condensation of vapors contacting same, is prevented so as to preclude gravitation of resulting condensate into the bottom of chamber 11 to dilute residuum product. Chamber 11 is provided in accordance with this invention for utilization alone or in combination with feed preparation chamber 28 in which feed to be processed in chamber 11 is pretreated. Chamber 28 is preferably upright having a lowermost portion 29 with a cross section smaller than that of the remainder of the chamber, i.e., chamber 28. Any suitable baflie or tray means 31 is employed in chamber portion 29 so as to cause fluids passed therethrough to follow a tortuous path. Baffies 31 are advantageously bubble cap type plates, although any suitable bafiie means or packing can be utilized. Stripping gas inlet 51 is in communication with a lower section of chamber portion 29 so as to direct stripping fluid upwardly therethrough in contact with a thin film or layer 'gravitating through chamber portion 29, admitted into chamber 28 at a point above chamber portion 29 via line 33.

Line 10 connects with chamber portion 29 at a point below conduit 51 for withdrawal of liquid. Conduit 51 communicates with the interior of chamber portion 29 at a point above the level of liquid therein. Conduit 33' provides for discharge of light gas, including stripping gas, from chamber 28.

In the operation of process illustrated with reference to Figure 1, a hydrocarbon residuum such as residuum from vis-breaking, or topped crude cracking, is introduced into chamber 28 via line 33, i.e., into the empty section thereof. Steam is introduced into chamber portion 29 via line 51 and is passed through chamber portion 29 in countercurrent flow with liquid charge passing over batfle means 31 as a film or a thin layer so as to strip light components from the charge. Steam and light ends are withdrawn via line 33'. Stripped heavy feed accumulates in the bottom-most portion of chamber portion 29, the level of which is maintained below the point of introduction of steam from conduit 51. Collected liquid is withdrawn from chamber portion 29 via line 10 and passed into the flash section 32 of chamber 11 under flashing conditions and as spray emitted from spray means 27 in a downwardly direction. Unvaporized liquid, i.e., residuum pitch product is accumulated in chamber portion 26 and is withdrawn via line 24 and is recycled via line/3 4 to the J collected body of liquid in chamber portion 29. Part of the liquid from line 24 is removed as product via line 50. Recycling in this manner provides for maintenance of a higher flash temperature in zone 32 and for a greater depth of flash than would be otherwise achieved.

Thus, feed from chamber 28 via line 10 introduced into chamber 11 has had the light ends removed therefrom. Entrainment of liquid particles in vapors from flashing in zone 32 is substantially prevented. Substantially no frothing takes place in zone 32. Because of the abscence of such light ends, this invention provides for an improved separation of unvaporized feed particles from Vapors formed by the feed flashing and no further step is required for effecting removal of the said entrainment prior to condensing the said vapors to form clean condensate product. Thus, in conventional operation, vapors formed from feed flashing contain unvaporized particles of feed as contaminants, the resulting condensate product being thereby contaminated and unfit, in many instances, as feed to other conversion processes requiring clean condensate feed.

Clean vapors produced in zone 32 in chamber 11 ascend from zone 32 into condensing zone 36, against deflecting dome plate 14, insulated on its upper surface as described above, so as to contact cool condensing spray from spray assemblies 13 and 13a. The vapors are sub jected to substantially no restriction to flow prior to being condensed, and therefore substantially no pressure drop is encountered in this section of the tower. Spray emitted from assemblies 13 and 13a, and resulting condensate, are collected in trough 12. Clean condensate product in trough 12 (including emitted spray) is removed via line 23 to storage tank 3'7. Line 325 communicates with the top of tank 37 and with condensing section 36 as an equalizing pressure line to allow condensate to be withdrawn from trough 12. Collected liquid in chamber 37 is withdrawn, cooled in cooling zone 39 and removed in part as heavy gas oil product in line 41 and returned in part via line 42' as feed to spray assemblies 13 and 13a. Thus, the emitted spray from assembly 13 is of substantially the same composition as that of vapors contacted therewith so that product withdrawn from trough 12 is a selected heavy gas oil product fraction of the process.

Vapors not condensed in zone 36 ascend upwardly through trough 16, passing against the bottom side of tray 18 being thereby deflected around tray 18 and conduits 21, and are contacted with cool liquid spray from spray nozzle assembly 17, the latter directed toward baflie section 19, adapted to deflect liquid droplets entrained in vapors passed therethrough, i.e., through baffle arrangement 19 so as to cause vapors passing therethrough to follow a tortuous path and to throw out any liquid particles of entrainment for collection in glay 18 together with emitted spray from spray assem- The temperature of the under side of tray 18 is maintained at a level sufliciently low that some condensation of vapors contacting same generally takes place. Droplets of such condensate, which ordinarily would gravitate toward the bottom of chamber 11 are in part picked up or swept by ascending vapors, the droplets impinging the upper side wall of chamber 11, down which droplets are permitted to gravitate and are collected in collecting trough 16.

Condensable vapors not condensed in contact with spray from nozzle assembly 17 are condensed in contact with baflle means 19, wetted with the cool emitted spray from assembly 17, the baffle thus cooled providing for an abundance of cooling surface for eflecting final con densation of condensable vapors. Total condensate formed in contact with spray from assembly 17 and with baflies 19, is gravitated onto tray 18 and comprises light gas oil condensate product. Any condensate gravitating 2 from the bottom side of tray 18 onto dome plate 14 is accumulated in collector trough 12.

Conduit 42 communicates with the upright enclosure in chamber 11, having the side Walls formed by tray 18 and baflies 19, and with a vacuum producing means 43 outside chamber 11, such as a system of steam jets 43.

Condensate product from collecting means 16 is withdrawn via line 22 and passed to storage vessel 44. Equalizing pressure line 46 communicates with the top of storage 44 and zone 47 above trough 16, as an equalizing pressure line to permit pumping of product from trough 16. Liquid from storage 44 is withdrawn via line 48 and recovered in part as light gas oil product of the process and is recycled in remaining part via cooler 49 for cooling to a temperature sufliciently low so as to effect condensation of vapors contacted therewith and then passed as feed to spray assembly 17. Thus, liquid collected in tray 18, and otherwise collected in trough 16, comprises clean light gas oil condensate product.

As illustrated with reference to Figure 6, the bottom side of tray 18 can comprise an arrangement of fins downwardly extending to effect improved cooling of vapors contacted therewith to effect condensation of the relatively heavier components therein and also to direct flow of vapors toward the side wall of chamber 11 carrying with them, as entrainment, the formed condensate for collection ultimately in trough 16. The fins are, in such an embodiment, advantageously radially disposed and provide for an initial condensation thereby reducing condensation requirements subsequently carried out, and also for recovery of condensate in trough 16 rather than permitting quantities of condensate to gravitate into trough 12 With reference to Figures 2A, 2B and 2C are shown cross sectional plan, side, and perspective views of the arrangement in chamber 11 of spray assembly 17, baffle assembly 19, and tray 18 of Figure 1.

In Figure 3A is shown a front view of the assembly of sprays 13, trough 12 and dome plate 14 in chamber 11 of Figure 1. In Figure 3B is shown a plan view of nozzle assembly 13 disposed so as to emit spray toward the periphery of chamber 11.

Figure 4 is illustrative of a preferred spacing of nozzles employed in spray assemblies 13 and/or 17 of chamber 11 of Figure 1.

With reference to Figure 5 is shown a distillation chamber 11', illustrative of one embodiment of this invention in which the liquid collecting means 12 is disposed in a central portion of chamber 11 rather than adjacent the side wall, and wherein spray nozzle assembly 13 is adapted and arranged so as to each direct flow of spray in a direction opposite that shown in chamber 11. Thus, in carrying out a process of this invention, in Figure 5, vapors from flash zone 32' ascend upwardly to a point above liquid collecting means 12 and thereabove in unobstructed contact with cool spray emitted from spray assemblies 13 and 13b so as to direct at least a portion of vapors into collecting means 12. Remaining uncondensed vapors are then passed upwardly to a point above a second liquid collecting means 16 and thereabove in contact with condensing sprays 17' to be condensed. Resulting condensate is collected in tray 18'. Tray 13 together with conduits 21 is adapted so as to transfer the condensate collected therein to liquid collecting means 16 while preventing contact of upwardly rising vapors with the condensate being transferred. Condensate product fractions are recovered from chamber 11 via lines 22 and 23' and residuum product is withdrawn via line 24. It is, thus, seen that my invention, in accordance with a broad concept, provides for (1) the step of removing light ends from the feed, (2) the step of flashing, (3) intermediate steps of cooling to produce condensate, (4) steps for collection of condensate product fractions and (5) recovery of same, although the various embodiments, as for example, ap-

paratus and process illustrated with reference to Figures 1 and 5, are not necessarily equivalents.

Although spray nozzle assemblies 17 and 17 are shown to direct spray toward baffle 19, either or both can, if desired, be adapted to direct spray towards the inner periphery of chamber 11 or 11'.

Stripping temperatures employed in chamber portion 29 are dependent on the specific feed stock treated, although temperatures of from 800 to 900 F. are advantageously employed. Steam as a stripping gas is now preferred, although any suitable stripping gases can be employed, as for example nitrogen, or residue (oxygenand sulfur-free) gases.

With reference to Figure 7, liquid collector means 12a is a trough-like member transversely disposed in chamber 11 in close proximity to the inner chamber wall. Spray nozzle assembly 13" is adapted and disposed to emit atomized droplets toward the inner periphery of chamber 1 1" from points on a locus extending upwardly from 12a to a central portion of chamber 11" below spray assembly 1312. A plurality of spaced apart bafiles 101 are disposed in chamber 11" so as to extend laterally from points on or in close proximity with the said locus. Preferably one or more of these bafiles, generally all, terminates in form of a trough 102 having a serrated edge 91; (Figure 9) and a conduit through the bottom thereof (Figure 9). In the operation of the embodiment of Figure 7, tip-flowing vapors in zone 36a are passed, as shown by arrows, in contact with cooling spray from 13 and resulting sprayed droplets and condensate are deflected for collection on a battle 10-1, whereby total liquid falls from one such bafile to a baflie adjacent thereto either by way of the conduit 9a or by overflow via the serrated edge 9b. Vapors not yet condensed, flowing along a path around the deflectors 101, are necessarily passed through separate curtains of falling liquid, descending either via conduit 9a or over serrated edge 91) whereby to again effect liquid vapor contact so as to facilitate maximum condensation.

With reference to Figure 8, liquid collector means 12b is a trough like member transversely disposed centrally in chamber 11. Spray nozzle assembly 13' is adapted and disposed to emit atomized droplets toward an inner portion of chamber 11" from points on a locus extending upwardly from collector 12!) toward the inner chamber periphery. A plurality of spaced-apart baflles 101 are disposed in chamber 11" so as to extend from points in close proximity to or on the said locus toward a central portion of chamber 11'. Preferably one or more of deflector baflles 10 1' terminate in form of a trough 192', having a serrated edge 9b (Figures 9A and 9B) and a conduit in 9a through the bottom thereof (Figures 9A and 9B).

In the operation of the embodiment of Figure 8, vapors ascending from zone 36b, pass in contact with sprayed liquid emitted from assembly 13, toward a central portion of chamber 11". Resulting condensate and sprayed liquid being deflected by tbaflles 101 so as to collect thereon and descend via conduit 9a and generally over the serrated edge 9b of trough 101', whereby to provide recontacting vapor yet uncondensed with a double curtain of descending liquid so as to achieve maximum degree of vapor condensation.

A horizontally disposed spray assembly 13b" can be employed in chamber 11" for directing cooling spray in contact with vapors uncondensed when passed in contact with sprayed liquid from spray assembly 13". Horizontal spray assembly 13b in the embodiment of Figure 7 is similarly employed.

Uncondensed vapors subsequent to contact with liquid in accordance with process of Figures 7 and 8, can be subjected to further condensation in accordance with the embodiments of Figures 1 and/or 5, when desired.

My invention is illustrated by way of the following 9 example with reference to the schematic flow operation of Figure 1 such as discussed hereinabove,

The charge to stripper 28 was visbroken topped crude, 8.0 API at 60 F.

Example Volume,

barrels Temp, per hour F. API

I. Fresh charge to stripper 28 162 750 Recycled residuum (line 34) 220 700 Total feed to chamber 11"... 382 720 II. Residue from chamber portion 26- 301 700 2 Residue yield 81 700 2 Recycle residuum (line 34)--- a 220 700 -2 Temperature lnflash zone 32, 700 F- Pressure in flash zone 32, 2 mm. Hg Abs. III. Heavy gas oil from trough 12 485 400 18. 5 Heavy gas oil yield I 75 300 18. 5

Heav as 011 to sprays 13 and l a 410 300 18, 5 IV. Light gas oil from trough 16 183 140 36.0 Light gas oil yield 6 140 36. Light gas oil to sprays 17"..- 177 1 20 as. 0

Pressure drop across chamber 11 was 0.16 rum. Hg. 7

Any suitable condition of temperature, pressure, vapor and liquid flow rates, and the like can be employed and are selected consonant with characteristics of the specific feed stock to be distilled. However, in a preferred form, this invention is' applied to the vacuum distillation of hydrocarbon residua and, when so applied, feed stock is advantageously charged to the flash zone at a temperature from 600-900 F. and the minimum over-all absolute pressure is preferred, which, as a result of the arrangement of apparatus of this invention, can be achieved in the range of from 0.001 to 2.0 mm. Hg absolute, as desired. In view of the liquid product collecting means, vapor condensation means, and the arrangement of same as described with reference to chambers 111 and ll, improved low pressure drop 'is achieved across the distillation vessel together with an improved low over-all distillation pressure than has been achieved heretofore, an over-all distillation pressure as low as about 0.10 mm. Hg being achieved when vacuum distilling a topped crude cracking residuum to produce clean gas oil fractions and, high softening point pitch residue.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawings, and the appended claims to this invention, the essence of which is that (l) entrainment of unvaporized feed particles in vapors from flash vaporization of a heavy liquid is substantially prevented by first stripping the noncondensable gas and light ends from the liquid to be flashed; (2) apparatus is provided in which a heavy liquid can be distilled, comprising an upright chamber containing cooling-spray and condensate-spray means, and condensate collection means, especially suitable for vacuum distillation of hydrocarbon oils; (3) a combination of apparatus is provided including a distillation chamber and feed preparation chamber wherein, in the latter, light ends of feed are removed therefrom prior to passing the stripped feed to distillation; (4) a stripp ng gas is passed in contact with a heavy liquid distillation feed, the latter as a thin film or layer at an elevated temperature, to provide forremoval of light ends therefrom prior to charging it to distillation; (5) a method is provided such as can be carried out in the apparatus referred to hereinabove for effecting distillation of liquids, such as heavy hydrocarbon oils, which method when employing subatmospheric pressures, utilizes improved low pressure and low pressure drop conditions; and (6) a -16 combination of steps is provided wherein, in a first step, light ends are removed from a heavy hydrocarbon liquid to be vacuum distilled and resulting stripped liquid is then passed to the vacuum distillation and distilled therein to provide clean gas oil condensate product fractions and high melting point residual pitch product.

I claim: 1

1. In a distillation of a heavy liquid, the method which comprises introducing said liquid into a lower portion of an upright distillation Zone; passing vapors formed from said liquid in said zone upwardly to a point above a first liquid collecting means and above said means into unobstructed contact with a cooling spray so as to condense a portion of said vapors into said first liquid collecting means; passing remaining uncondensed vapors upwardly to a point above a second liquid collecting means and above said second liquid collecting means into contact with a vertically extended laterally directed condensing spray to condense remaining vapors; collecting condensate in a condensate collector means disposed beneath said condensing spray and so adapted and arranged as to transfer said collected condensate to said second liquid collecting means while preventing contact of upwardly rising vapors with said condensate being transferred; and transferring said collected condensate from said condensate collector means to said second liquid collecting means.

2. In a vacuum distillation of a hydrocarbon residuum, the method which comprises introducing said residuum into a lower portion of an upright distillation zone; passing vapors formed from flash vaporization of said residuum in said zone upwardly to a point above a first liquid collecting means and above said means into unobstructed contact with a vertically extended laterally directedcooling spray so as to condense at least a portion of said vapors into said first liquid collecting means; passing remaining uncondensed vapors upwardly to a point above a second liquid collecting means and above said second liquid collecting means into contact with a condensing spray to condense remaining vapors; collecting condensate in a condensate collector means disposed beneath said condensing spray and so adapted and arranged as to transfer, said collected condensate to said second liquid collecting means while preventing contact of upwardly rising vapors with said condensate being transferred; transferring said collected condensate from said condensate collector means to said second liquid collecting means, recovering condensate from at least one of said first and second liquid collecting means, and recovering residuum from a lowermost portion of said distillation zone.

3. The method of claim 2 wherein vacuum is applied to said distillation zone at a point above said condensing spray and withdrawing any uncondensed gases from said zone via the vacuum producing means.

4. In the vacuum distillation of a hydrocarbon residuum wherein the said residuum is partially flashed and particles of entrained heavy liquid remain in resulting vapors and wherein product of condensation of said vapors contains particles of said residuum as contaminant, the improvement comprising contacting residuum feed in form of a film, with steam under elevated temperature conditions so as to strip light components from said residuum; introducing resulting stripped feed into an upright distillation zone maintained under subatmospheric pressure, under flashing conditions; passing resulting vapors from said flashing upwardly through a central portion of said distillation zone, in contact with a vertically extended laterally directed spray of cooler liquid directed toward the outer extremities of said distillation zone, whereby condensation of a portion of the said vapors takes place; collecting resulting condensate and sprayed droplets at a point below the zone of the last said contacting, and recovering liquid thus collected, free from heavy liquid contaminants, as

product; passing remaining uncondensed vapors upwardly in said zone in contactwith a vertically extended laterally directed condensing spray so as to effect condensation of condensable portions thereof, and then through a liquid particle deflecting zone so as to arrest particles entrained in residual vapors from the last said condensation; collecting droplets from the last said spray together with condensate formed in contact therewith at a point below the zone of the last said contacting, and recovering the collected spray and condensate, free from residuum feed contaminants, as product; and recovering residuum as distillation product from a lowermost portion of said distillation zone.

5. In a distillation of a liquid, the method which comprises introducing only liquid into a flashing zone in a lower portion of an upright distillation zone, passing vapors formed from said liquid in said zone upwardly through a confined zone, spraying a cool liquid into unobstructed contact with said vapors in a vertically extended laterally directed spray zone to condense a portion of said vapors, collecting the condensed vapors and liquid, passing remaining uncondensed vapors upwardly through a second confined zone, spraying a cool liquid into contact with remaining vapors, and collecting the condensed vapors and liquid.

6. In a vacuum distillation of a hydrocarbon residuum, the method which comprises introducing only said residuum into a lower portion of an upright distillation zone, passing vapors formed from flash vaporization of said residuum in said zone upwardly through a confined zone, spraying a cool liquid into unobstructed contact with said vapors in a vertically extended laterally directed spray zone to condense a portion of said vapors, collect" ing the condensed vapors and liquid, passing remaining uncondensed vapors upwardly through a second confined zone, spraying a cool liquid into contact with remaining vapors, collecting the condensed vapors and liquid, recovering condensate from at least one of the first and second collection zones, and recovering residuum from a lowermost portion of said distillation zone.

7. The method of claim 6 wherein vacuum is applied to said distillation zone and any uncondensed gases are withdrawn from said distillation via the vacuum producing means.

8. In the vacuum flash vaporization of a heavy distillable liquid wherein said liquid is flashed in a flashing zone, the improvement comprising passing vapors formed in said flashing zone from said flashing zone upwardly through a longitudinally extended radially directed spray zone of cool liquid, contacting said vapors with said cool liquid and condensing a portion of said vapors, and collecting said cool liquid and condensate.

9. In the vacuum flash vaporization of a heavy distillable liquid wherein said liquid is flashed in a flashing zone, the improvement comprising spraying a cool liquid into the space above said flashing zone in a lateral direction from a plurality of points located equidistant from a longitudinally extended axial line to form a spray zone, passing vapors formed in said flashing zone upwardly into said spray zone, contacting said vapors with said cool liquid and condensing a portion of said vapors, and collecting said cool liquid and condensate.

10. In the vacuum flash vaporization of a heavy distillable liquid wherein said liquid is flashed in a flashing zone, the improvement comprising spraying a cool liquid into the space above said flashing zone in a radial direction from a plurality of points located equidistant from a longitudinally extended axial line to form a spray zone, passing vapors formed in said flashing zone upwardly axially and radially through said spray zone, contacting said radially flowing vapors with said cool liquid and condensing a portion of said vapors, and collecting said cool liquid and condensate in a peripherally arranged cooling zone.

11. In the vacuum flash vaporization of a heavy distillable liquid wherein said liquid is flashed in a flashing zone, the improvement comprising spraying a cool liquid into the space above said flashing zone in an inwardly lateral direction from a plurality of points located equidistant from a longitudinally extended axial line to form a spray zone, passing vapors formed in said flashing zone upwardly peripherally and laterally through said spray zone, contacting said laterally flowing vapors with said cool liquid and condensing a portion of said vapors, and

collecting said cool liquid and condensate in an axially arranged collection zone.

12. An upright chamber; an inlet conduit in a lower side wall of said chamber; a first trough transversely disposed in a central portion of said chamber above said inlet conduit; a first spray nozzle assembly in said chamber forming sides of an upright member therein, spaced above said trough and adapted to direct spray toward an inner portion of said chamber; a horizontal-1y disposed spray assembly in said chamber positioned at the upper end of said upright member; a second trough transversely disposed in said chamber above said horizontal spray assembly; a baflie assembly in said chamber, disposed above said second trough so as to form side Walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said baflle assembly; a tray assembly adapted to close the bottom end of said upright enclosure and extending laterally beyond the said bafl le assembly and said second spray assembly; conduit means conveying fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for conveying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a. lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communica tion with the interior of said upright enclosure and a point outside said chamber.

13. An upright chamber; an inlet conduit in a lower side wall of said chamber; a first trough above said inlet conduit adjacent the inner wall of said chamber and transversely disposed in said chamber; a first spray nozzle assembly in said chamber forming sides of an upright member therein, and spaced above said first trough and adapted to direct spray toward the periphery of said chamber; means for closing the upper end of said upright member; a second trough transversely disposed in said chamber above said first spray nozzle asembly; a baflie assembly in said chamber, disposed above said second trough so as to form side walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said baflie assembly; a tray assembly adapted to close the bottom end of said upright enclosure and extending laterally beyond the said baflie assembly and second spray assembly; conduit means for conveying fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for conveying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communication with the interior of said upright enclosure and a point outside said chamber.

14. A first upright chamber having a lowermost portion of cross section smaller than the remainder of said chamber; a plurality of baflies disposed in said lowermost portion so as to cause fluid flowing therethrough to follow a tortuous path; a first conduit means connecting an uppermost portion of said first chamber with a point outside the said chamber; a second conduit means connecting a said lowermost portion of said first chamber with a point outside said chamber; a third conduit means in communication with the said lowermost portion of said first chamber at a point below said second conduit means; a second upright chamber; a fourth conduit means connecting with said third conduit means from said first chamber and disposed in communication with a lowermost portion of said second chamber; a fifth COIldIL'Llt means, in communication with a lowermost portion of said second chamber, at a point below said fourth conduit, and a point outside said chamber; a sixth conduit means in communication with an uppermost portion of said second chamber, at a point above said fourth conduit, and a point outside said chamber; a plurality of vertically extended laterally directed spray means for eifecting condensation of vapors in said second chamber above said fourth conduit; and a plurality of means for withdrawal of condensate from said second chamber without substantial contact with the vapor passing through said second chamber.

15. An upright chamber; an inlet conduit in a lower side wall of said chamber; a first trough transversely disposed in a central portion of said chamber above said inlet conduit; a first spray nozzle assembly in said chamber forming sides of an upright member therein, spaced above said trough and adapted to direct spray laterally toward an inner portion of said chamber; a horizontally disposed spray assembly in said chamber positioned at the upper end of said upright member; a second trough transversely disposed in said chamber above said horizontal spray assembly; a baflie assembly in said chamber, disposed above said second trough so as to form side Walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said baffle assembly; a tray assembly adapted to close the bottom end of said upright enclosure and extending laterally beyond the said baffle assembly and said second spray assembly; means for returning fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for conveying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communication with the interior of said upright enclosure and a point outside said chamber.

16. An upright chamber; an inlet conduit in a lower side wall of said chamber; a first trough above said inlet conduit adjacent the inner wall of said chamber and transversely disposed in said chamber; a first spray nozzle assembly in said chamber forming sides of an upright member therein, and spaced above said first trough and adapted to direct spray toward the periphery of said chamber; means for closing the upper end of said upright member; a second trough transversely disposed in said chamber above said first spray nozzle assembly; a baffle assembly in said chamber, disposed above said second trough so as to form side walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said bafile assembly; a tray assemblyadapted to close the bottom end of said upright enclosure and extending laterally beyond the said baffle assembly and second spray assembly; means for returning fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for conveying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communication with the interior of said upright enclosure and a point outside said chamber.

17. An upright chamber; an inlet conduit means communicating with the lower portion of said upright chamher; a first trough above said inlet conduit adjacent the inner wall of said chamber and transversely disposed in said chamber; a first spray nozzle assembly in said chamber forming sides of an upright member therein, and spaced above said first trough and adapted to direct spray toward the periphery of said chamber; means for closing the upper end of said upright member; a second trough transversely disposed in said chamber above said first spray nozzle assembly; a baflle assembly in said chamber, disposed above said second trough so as to form side walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said baflie assembly; a tray assembly adapted to close the bottom end of said upright enclosure and extending laterally beyond the said baflle assembly and second spray assembly; conduit means for conveying fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for com veying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communication with the interior of said upright enclosure and a point outside said chamber.

18. An upright chamber; an inlet conduit means communicating with the lower portion of said upright chamber; a first trough transversely disposed in a central portion of said chamber above said inlet conduit; a first spray nozzle assembly in said chamber forming sides of an upright member therein, spaced above said trough and adapted to direct spray toward an inner portion of said chamber; a horizontally disposed spray assembly in said chamber positioned at the upper end of said upright member; a second trough transversely disposed in said chamber above said horizontal spray assembly; a baffle assembly in said chamber, disposed above said second trough so as to form side walls of an upright enclosure; a second spray nozzle assembly in said chamber in close proximity to the sides of said upright enclosure and adapted and arranged to emit spray toward said bafile as sembly; a tray assembly adapted to close the bottom end of said upright enclosure and extending laterally beyond the said baflle assembly and said second spray assembly; conduit means conveying fluid from said tray assembly into said second trough; said first spray nozzle assembly being spaced in relation to said first trough so as to cause sprayed particles therefrom to collect in said first trough; conduit means for conveying fluid flow from each of said troughs to a point outside said chamber; conduit means connecting a lower portion of said chamber at a point below said inlet conduit to a point outside said chamber; and conduit means in communication with the interior of said upright enclosure and a point outside said chamber.

19. A liquid condensing apparatus comprising an upright trap chamber having two side walls disposed opposite each other, two baflie assemblies disposed opposite each other between the two said side walls and at right angles to said two side walls, a tray assembly adapted to close the bottom end of said upright trap chamber and extending laterally beyond the said baflle assemblies, two spray nozzle assemblies each disposed between the two said side walls and adapted and arranged to emit spray inwardly toward each of said bafiie assemblies, and conduit means for conveying fluid from said tray assembly to a peripheral zone of a vessel in which said condensing apparatus is placed.

20. An upright chamber; inlet conduit means communicating with a lower portion of said chamber; a first i liquid collecting means above the communication of said inlet conduit means with said chamber, disposed in said chamber and adapted to permit vapor flow upwardly in said chamber from a point below to a point above said first liquid collecting means and above said first liquid collecting means into unobstructed contact with a spray from a first spray means described hereinafter; a first spray means in said chamber spaced above said first liquid collecting means and so adapted and arranged as to direct spray into said vapor flow to condense at least a portion of said vapors and to cause condensate thus formed to collect in said first collecting means; a second liquid collecting means disposed in said chamber above said first spray means and adapted to permit vapor flow upwardly in said chamber from a point below to a point above said second liquid collecting means and above said second liquid collecting means into contact with a spray from a second spray means described hereinafter; a second spray means in said chamber above said second liquid collecting means so adapted and arranged as to direct spray into contact with vapors above said second liquid collecting means to condense at least a portion of said vapors; a collecting tray disposed below said second spray means and above said second liquid collecting means and transversely of vapor flow above said second liquid collecting means; means for conveying liquid from said tray to a point substantially vertically above said second liquid collecting means; conduit means communicating with an upper portion of said chamber above said second spray means and with a point outside said chamber; conduit means communicating with a point in said chamber below the point of communication of said inlet conduit means, with a point outside said chamber; conduit means connnunicating with said first liquid collecting means and with a point outside said chamber; and conduit means communicating with said second liquid collecting means and with a point outside said chamber.

21. Apparatus of claim 20 wherein said first spray means is a spray nozzle assembly adapted to emit liquid spray in a direction toward the inner wall of said chamher; and wherein a plate is transversely disposed in said chamber, above said first spray nozzle assembly, adapted and arranged so as to cause vapors rising upwardly in said chamber toward said plate to be deflected in direct contact with emitted droplets from said first spray nozzle assembly.

22. In the apparatus of claim 20 a plurality of laterally disposed fins on the under side of said collecting tray adapted to direct vapors flowing upwardly in contact therewith, toward a side wall of said chamber.

23. Apparatus of claim 20 wherein at least one of said first and second liquid collecting means is a trough disposed in a central portion of said chamber and wherein the spray means associated with such a centrally disposed trough is adapted to emit spray toward said central chamber portion.

24. Apparatus of claim 20 wherein said second spray means is adapted to emit spray in a direction toward an inner peripheral portion of said chamber and against a plurality of baflles arranged so as to deflect entrained droplets in vapors passed therethrough.

25. In the apparatus of claim 20 a plurality of laterally disposed on the under side of said collecting tray extending radially from the axis of said tray to the peripheral edge of said tray and adapted to direct vapors flowing upwardly in contact therewith, toward a side wall of said chamber.

26. Apparatus of claim 20 wherein a lowermost portion of said chamber below the point of communication of said inlet conduit means is of cross section smaller than 11 6 the remainder of said chamber; and said spray means in said chamber connected with said inlet conduit are directed toward said lowermost portion.

27. Apparatus of claim 26 wherein said inlet conduit means is also in open communication with a second upright chamber at a point in a lowermost portion thereof; the last said lowermost portion having a cross section smaller than that of the remainder of said second chamber; baflle means in the lowermost portion of said second chamber, adapted to cause fluid, passing therethrough, to follow a tortuous path; inlet conduit means in communication with the last said lowermost chamber portion and with a point outside said chamber portion; conduit means in an upper portion of said second chamber for admitting and withdrawing fluid therefrom; and outlet conduit means in communication with a bottom section of said lowermost portion of said second chamber at a point outside said second chamber.

28. Apparatus of claim 20 wherein said first liquid collecting means is a trough peripherally disposed in said chamber; wherein said first spray means is a spray nozzle assembly adapted to emit atomized droplets toward the periphery of said chamber from points on a locus extending from said first liquid collecting means to a central point in said chamber; and a plurality of spaced apart baflles in said chamber extending laterally therein from points in close proximity to said locus.

29. Apparatus of claim 28 wherein at least one of said baflles terminates in form of a trough, wherein a conduit is disposed through a bottom portion of said trough, and wherein the outer edge of the last said trough is serrated.

30. Apparatus of claim 20 wherein said first liquid collecting means is a trough disposed centrally in said chamber; wherein said first spray means is a nozzle assembly adapted to emit atomized droplets toward a central portion of said chamber from points on a locus extending from said first liquid collecting means toward the periphery of said chamber; and a plurality of spaced apart baflles in said chamber extending from points on said locus toward said central chamber portion,

31. Apparatus of claim 30 wherein at least one of said bafiles terminates in form of a trough, wherein a conduit is disposed through a bottom portion of the last said trough, and wherein the outer edge of the last said trough is serrated.

32. Apparatus of claim 20 wherein at least one of said first and second liquid collecting means is a trough transversely disposed in said chamber.

33. In the apparatus of claim 32 insulation means disposed on the upper surface of said transversely disposed plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,455,546 Moscicki May 15, 1923 1,945,600 Coubrough Feb. 6, 1934 1,953,730 Stratford Apr. 3, 1934 2,002,731 Coubrough May 28, 1935 2,003,306 Perl June 4, 1935 2,073,446 Ellsberg Mar. 9, 1937 2,095,418 McConnell Oct. 12, 1937 2,125,325 Youker Aug. 2, 1938 2,141,829 Sohneible Dec. 27, 1938 2,376,923 Kraft May 29, 1945 2,674,570 Potts Apr. 6, 1954 2,698,282 Findlay Dec. 28, 1954 2,774,723 Moyer Dec. 18, 1956 2,805,981 Cavin et al. Sept. 10, 1957 

2. IN AS VACUUM DISTILLATION OF A HYDROCARBON RESIDUUM THE METHOD WHICH COMPRISES INTRODUCING SAID RESIDUUM INTO A LOWER PORTION OF AN UPRIGHT DISTILLATION ZONE; PASS ING VAPORS FORMED FROM FLASH VAPORIZATION OF SAID RESIDUUM IN SAID ZONE UPWARDLY TO A POINT ABOVE A FIRST LIQUID COLLECTING MEANS AND ABOVE SAID MEANS INTO UNOBSTRUCTED CONTACT WITH A VERTICALLY EXTENDED LATERALLY DIRECTED COOLING SPRAY SO AS TO CONDENSE AT LEAST A PORTION OF SAID VAPORS INTO SAID FIRST LIQUID COLLECTING MEANS; PASSING REMAINING UNCONDENSED VAPORS UPWARDLY TO A POINT ABOVE A SECOND LIQUID COLLECTING MEANS AND ABOVE SAID SECOND LIQUID COLLECTING MEANS INTO CONTACT WITH A CONDENSING SPRAY TO CONDENSE REMAINING VAPORS; COLLECTING CONDENSATE IN A CONDENSATE COLLECTOR MEANS DISPOSED BE NEATH SAID CONDENSING SPRAY AND SO ADAPTED AND ARRANGED AS TO TRANSFER SAID COLLECTD CONDENSATE TO SAID SECOND LIQUID COLLECTING MEANS WHILE PREVENTING CONTACT OF UPWARDLY RISING VAPORS WITH SAID CONDENSATE BEING TRANSFERRED; TRANSFERRING SAID COLLECTED CONDENSATE FROM SAID 